Welding apparatus



10, 1934-- H. T. PLA-rz WELDING APPAnTUs original Filed Nv. 9, 1931 il, l. I! Il ll Il il l l:

ATTO RNEYJ Patented Apr. 1o,- 1934:

PATENT'- ,oFFicE WELDING APPARATUS .Henry Thomas Platz, Detroit, Mich., assigner to Briggs Manufacturing Company, Detroit, Mich.,

a corporation of Michigan Uoriginal application August 1s, 1931, serial No.

476,127. Divided and this applicationNovember 9, 1931, Serial No. 573,970. Renewed Janne ary 18, 1934 'z calms. (el. 20c-sz)4 This invention relates vto welding apparatus and has as one of its objects'to simplify, render 4more eflcient and improve generally devices of this lcharacter.

5 This application is a division of my copending application Serial No. 476,127 filed August 18, 1931, entitled Welding apparatus.

. The invention contemplatesthe provision of welding apparatus having relatively movable electrodes engageable with the partsto be welded and having means controlled by relative movement of the electrodes into operative position for automatically closing an electric circuit to the electrodes to perform the welding operation. Another object of this invention is to provide welding apparatus of the type outlined above wherein relative movement of the electrodes into operative position and wherein opening and closing `the electric circuit to the electrodes is automatically effected `in timed relation to the movement of the electrodes by iiuid pressure, lthereby reducing the number of parts and as a consequence the cost of manufacture `to a minimum. s f y Another advantageous feature of this invention is to provide means for variably controlling thel fluid pressure for actuating the circuit controlling means so as to permit accurately regulating the length of th weld. A further-advantageous feature of the present invention resides in the provision of a pair of relatively movable electrodes engageable with opposite sides of the work and designed to yieldably clamp the latter therebetween. With thev above arrangement, it will be apparent that the electrodesY will automatically adjust themselves to accommodate work of varying dimension and also that the pressure exerted upon the work by the 50 vice 10, it will be noted from the drawing that this device comprises a pair of cooperating opposed relatively movable electrodes 23 and 24 supported in axial alignment with each otherI in the le'gsl25 and 26, respectively, of `a substantially U-shaped frame member 27. The electrode 23 of the frame 27 for movement relative to the is threadedly mounted within the inner end of a sleeve 28 extending through an opening in the les 25 and closed at the outer end thereof by means of a plug 29. The sleeve 28 is anchored within and insulated from metallic contact with the leg 25 by'means of a sleeve 30 surrounding the sleeve 28 and formed of any suitable insulating material. The outer end of the sleeve 28 preferably projects beyond the leg 25 and is adapted to receive a ring 31 having a recess 32 therein intermediate the ends thereof communicating with the interior of the sleeve 28 by means of a suitable passage 33. The ring 31 is provided with a lateral extension 34 having a passage 35 therein communicating with the recess 32 and also 'with -a conduit 36 extending axially through the electric conductor 37 which is preferably formed of a plurality of electric wires 38 and is connected to the transformer (not`shown). The electric' wires 38 are adapted to contact with the extension 34 and supply electrical energy through the ring 31 and sleeve 28 to the electrode 23. As shown, the plug 29, sleeve 28 and ring 3l are provided with aligned passages establishing communication between a flexible tube 39v and a metallic tube 40 having the'outer end thereof anchored within the plug 29 and extending axially through the sleeve 28 within a counterbored portion 41 of the electrode 23. The tube 39 is preferably` connected to a suitable source of cooling medium with the result/'that the latter is caused to flow through the flexible tube 39 into the tube 40 and into the electrode 23 for cooling the latter. In this connection it is to be noted that the diameter of the tube 40 is considerably lessthanthepassage 41 within the electrode 23 so as to permit the cooling medium to ow from the inner` end of the tube 40 outwardly through the recess 41 andV sleeve 28 `to the recess 32 in the ring 31. From the recess 32 the cooling medium is directed through thev passage 35 in the extenslon'34 into -the tube 36 where it may be disposed of in any suitable manner.

`The electrode 24 is supported by the leg 26 electrode 23 and, as wiu beobserved; is threaded- 0 ly mounted within the outer end of a recess v42 formed in the correspondingend of a plug 43 having a ring 44 encircling the outer end portion thereofl and provided with anY internal annular recess 45 communicating by means ofmthepassage 46 inthe recessed portion of the plug 43 with the recess 42 in the latter. The ring 44 is provided with a lateral extension 47 having a passage 48 therethrough communicating at-one end with the annular recess 45 in they ring 44 and at the opposite end with a flexible tube 49 extending axially through the conductor 50 sim-- ilar in construction to the conductor -37 but extending from -the opposite side of 'the circuit. The conductor 50 is connected into the trans--` former 21 at one end and is electrically connected to the extension 47 at the opposite end so as to establish an electrical connection with the electrode 24. The flexible tube 49 preferably extends 'from the-transformer cooling circulatorysystem so as to convey the cooling medium into the re- Ivcess 42 through the various passages previously described. After fthe cooling medium is deposited within the recess 42, it is caused to iiow through a re'cess 51 formed in the electrode 24 to cool the same. The cooling medium is then permitted to ow through a tube 52 arranged within the recess 51 and communicating with the exible tube 39. by means ofthe passage 53. From the flexible tube` 39 the cooling medium is discharged into the electrode 23 as previously described.

Threadedly mounted upon the inner end of the plug 43I is a sleeve 54 slidably engaging within a sleeve 55 which in turn is reciprocably mounted within a bushing 56 anchored within an opening formed in-the leg 26 of the U-shaped frame 27. AArranged within the sleeves 54 and 55 is aspring \57 having the outer end thereof engaging the plug 43 and the inner end engaging a closure vmember 58 threadedly mounted within the inner end of the sleeve 55. The spring 57 normally urges the plug 43 and accordingly the electrode 24 to theiroutermost positions which'is limitedy \by engagement of the cooperating shoulders 59 and 60 on the sleeves 54 and 55, respectively. In this connection it is to be noted that the sleeve 54 is provided with a pin 61 engageable in a slot 62 formed in the sleeve 55. The slot is of sufcient length to permit the required relative movement of the parts and the side walls thereof engages opposite sides of the pin so as to hold the sleeves 54 and 55 while assembling or removing the plug. With the above construction, it

'will be apparentthat the electrode 24 yieldably clamps the work against the electrode 23 with the 'result that the clamping pressure exerted ,by the electrode 24 is maintained substantially constant as the parts to be welded are fused together. It

' will further be seen that by reason of the above construction the electrodes will automatically compensate for work of varying dimensions. The clamping force of the electrode 24 may be accurately controlled by adjusting the closure member 58 relative tothe sleeve 55 to change the length of the spring 57.

For actuating the sleeve 55 to effect a movev :ment oi' the electrode -24 to operative position,

' -fthe closure memb a? s The casting 68 is further provided` with a downthe inner end portion of the sleeve 55 is'provided with a radially outwardly extending circular ilange 65 slidably en aging the annular side walls 66 oi' a suitable cyl' 58 to form a piston. The cylinder 67 is formed within'a casting 68 secured as at 69 to the leg 26 of the -U-shaped frame 27.

' "wardly extending hand gripping DOIOR TOhaV- ylower'iend' thereof witha iluidv supply line 72 and atthe upper end with a reduced passage v73l which inv turn communicates with ja transversely `,ex-

inga recess '1l-'therein communicating at the tending'chamber '74.. Vl'teciprocably .mounted v within the chamber74 is avalve member 75 having a restricted -pi'issa'ge 76 therein adapted, in

one psition 'or vthe valve member, to. register der 67 and cooperating withwith the passage 73 and with a cooperating passage 77'leading into the iuid cylinder 6 7. Movement of the valve member to register the passages outlined above is. resisted by means of a spring 78 actingupon the valve member to normally 'urge the .same "outwardly from the chamber 74. The valve member 75 is manually'a'ctuated to register the passages 73, 76 and 77 by means of a trigger 79 pivoted as at 80 to the cast- .ing'and protected by means of the guard 81. A

The foregoingl construction is such that when it is desired to move the electrode 24 in operative positon,vthe operator merely actuates the trigger 79 to move the valve 75 to its innermost position at which time the passage 76 in the valve registers .with the passages 73 and 77 permitting fluid under pressure to ow into the cylinder 67.- When theA pressure of the fluid in the cylinder 67 exceeds the pressure of the spring 82 whiqrlgi 'serves to return the piston to its innermost position within the cylinder, the piston or sleeve 55 and plug 43 will be moved outwardly as a unit to engage the electrode 24 with the/work. In this connection it is to be noted that the electrode 2 4 Vengages the work to clamp the same to the electrode 23 before the piston reaches the end f its stroke with the result that the sleeve 55 continues to move outwardly until the shoulder of the ange 65 engages the end oi the sleeve 56 at which time the spring 57 is compressed and the electrode is yieldably clamped into engagement with the work. Upon release of the trigger 79, the valve 75 is moved outwardly under the iniiuence of the spring 78 preventing further flow of uid into the cylinder 67 and opening the passage 83 communicating at one end with the cylinder and at the other end witha port 84 which in turn communicates with the atmosphere to re, lieve the pressure within' the cylinder 67 and permit the piston to be returned to inoperative position under the influence of the lspring 82.

During inward movement of the sleeve 55 under that the shoulder 60 on lthesleeve- 5 5 will engage the shoulder 59 on the sleeve 54 to return the electrode 24 to its inoperative position.

As previously stated it is one of the objects of this invention to provide means for automatically closing the circuit tp the eiectrcdes'zs and 24 in timed relation to relative movement of the latter into clamping engagement with the work. For accomplishing the above result, I Vprovide a Aiiuid pressure operated switch 84' comprising a pair of contact members 85 and 86 'respectively connected by means of the electrical conductors the inner end of a piston-94slidably engaging within a cylinder 95. The innerend portion or vhead ofA the piston 94 is of'a greater'diameter than the b ody portion of the piston and lforms an annular shoulder 96adapted to engage a corresponding shoulder 97 in the cylinder 95 when -the action of the spring 82, it will be observed 87-t the control circuit of the welding device.f

the piston is in its outermost or inoperative position. The pistony is normally urged toits inoperative position or away from the contact points by a light spring 98 having the outer end engaging the piston and the inner end thereof engaging a suitable cap member 99. A suitable relief passage 100 is provided having the inner end thereof communicating with the cylinder adjacent the annular shoulder 97 and the outer end communicating with the atmosphere. The arrangement is such as to prevent the piston from building up a pressure in rear of the same during movement thereofto its inoperative position.

The cylinder 95 is arranged within a chamber 101 formed integral with the casting 68 to one side of the cylinder 67 and arranged in communication therewith in the following manner. Formed in the wall of the casting between the cylinders 67 and chamber 101 is a longitudinally extending passage 102 communicating at the outer end thereof with the chamber 101 by means of a passage 103 and communicating with the cylinder 67 adjacent'the inner end at predetermined distances from the inner end thereof by means of a pair o f longitudinally spaced passages 104 and 105. The passages 104 and 105 are normally sealed by the piston on the sleeve 55 so as to prevent the flow of fluid from the cylinder 67 into the chamber 101 through the passages establishing communication therebetween. The construction is such, however, that as the piston or sleeve 55 approaches its full stroke to move the electrode 24 into' clamping engagement with the work, the passages 105 and 104 will be progressively opened permitting fluid under pressure-to flow through the passages 102 and 103 into the chamber 65 behind the piston 94. As soon as the pressure of the fluid in rear of the piston 94 exceeds that of the coil spring 98, the piston 94 will be moved inwardly to bridge the contact pins and 86 by the member 91. Bridging the contacts 85 `and 86 by the member 9i closes the control circuit to close the circuit to the electrodes 23 and 24. From the foregoing it will be observed that the pressure operated switch'84 functions in timed relation to the relative movement of the electrodes into operative position. The time interval allowed' to elapse between the operation ofthe switch 84 and electrodes may be accurately regulated by means of a needle valve member 106 threadedly engagingi the chamber 101 and adapted to extend within the passage 103 to control the amount of fluid admitted to the chamber 101. i

AAnother object of the present invention broadly set forth in the preamble of thisspecication resides in the provision of means for automatically opening the pressure controlled switch 84' at -predetermined intervals to discontinue the .weld irrespective of the position of the manually controlled valve memberV 75. In order to accomplish the above function, the casting 68 is formed with a second cha er 107 communicating by means of a passage 08 with the cylinder 95 at a point in advance o the piston 94. The chamber 107 receives fluid under pressure from the passage 102 by means of a passage 109`communi- .cating at one end With.the passage 102 and at the opposite end with the cylinder vin advance of the piston 94 with the result that fluid under pressure flowing through -the passages 102 and 109 will be discharged into the cylinder 95 in advance of the piston 94 and fromv the cylinder 95 `will flow into the chamber 107 through the passage 108. Fluid 4will be discharged lfrom the cylinder 67 to the chamber 107 through th/e path outlined above until the pressure in the chamber 107 is substantially equal to the pressure in the cylinder .67 or in other words, is substantially vequal to the pressure -behind the piston 95, at

which time the piston 95'will` bemoved outward- Yso ly owing to the increased area of the outer end 'y thereof and to the slight pressure exerted by the and 86 and thereby open the circuit to the electo build up sufficient pressure in the chamber 107 for opening the circuit as outlined above and accordingly the length of the weld, may be accurately regulated by means of a needle valve 110 threadedly engaging the casting 68 and having a tapered end part lll for controlling the flow of uid from the passage 102 into the portion of the cylinder 95 in advance of the piston 94.

Thus, from the foregoing it will be apparent that I have provided a welding device having means automatically operable in timed relation to the movement of the electrodes into-engagement with the work tc be welded for closing the electric circuit to the electrodes and having additional means operable in timed relation to both of the aforesaid meansfor automatically opening the circuit to discontinue the weld. It will further be apparentY that both of the aforesaid means may be accurately regulated to control the g time intervals adapted to elapse between the closingand opening of the circuit to the electrodes.

What I claim as niy invention is': 1. A fluid pressure operated switch for a port- 'able weldingdevice comprising, a pairl of contact elements connected within an electric circuit and insulated from 'each other, a terminal bridge member for bridging the Contact elements to close the circuit, a piston connected to the bridge member, a cylinder within which said piston is adapted to reciprocate and communicating-at a point in rear of the ypiston with a source of fluid supply, yieldable means normally urging said piston and bridge member away from the contact elements, means for dischargingfluid under pressure in rear ofthe piston to urge the same forwardly to electrically connect the contact elements with the bridge member for closing the circuit, and means for regulating the iiow of fluid Ainto said cylinder for regulating the time of opermember for bridging the contacts to close the circuit, a cylinder, a piston reciprocably mounted within the cylinder and connected at the forward end thereof to said terminal member, a fluid pres- .sure chamber communicating with the cylinder in advance of the piston, means for discharging fluid under pressure in rear of the piston to move the latter and terminal bridge member into operative relation with the contact elements for closing the circuit, and means for simultaneously discharging fluid under pressure into said chamber for building up a pressure in advance of the piston for returning the latter and terminal member to inoperative position irrespective of the pressure inthe cylinder in rear of the piston.r

,3. A fluid pressure operated switch comprising a pair of insulated contact members connected to opposite sides of an electric circuit, a terminal member for bridging the contacts to close the circuit, a cylinder, a piston reciprocably mounted coil spring 98 to disconnect the contact pins 85 'within' the cylinder and connected ,at the for- Aber into operative relation with the contact elements for closing the circuit, means for simultaneously discharging a luidunder pressure into said chamber to buildup a pressure in advance of .the piston, and vmeans automatically operable when thepressure in the chamber reaches-a predetermined amount to return the piston and terminal'member to inoperative position.

4. A fluid pressure operated switch comprising a pair of insulated contact members connected to vopposite sides of an electric circuit, a terminal Amember for bridging the contacts to close the cir-l cuit, a cylinder, a piston reciprocably mounted within the cylinder and connected at' the forward end thereof to said terminal member,`a uid pres- -suregcha-mber communicating with thecylinder in advance of the piston, means for discharging uid under pressure in rear of the piston to move the latter and terminal bridge member into operative relation with the contact elements for closing the circuit, means for simultaneously discharging uid under pressure into said chamber for building up a' pressure in advance of the piston for returning the latter and terminal member. to inoperative position irrespective of the pressure in the cylinder in rear of the piston, and

means for controlling the ilow of fluid into said chamber and into the cylinder for regulating the operation of the pistonand terminal contact vsource of fluid pressure supply, spring means l 5. A pressure operated switch comprising` a pair of insulated contact elements 'connected to opposite sides of a. circuit, aterminal member adapted, to bridge the contact elements to close the circuit, a piston operatively connected to the 'terminal bridge member, a cylinder within which said-piston is reciprooably mounted; means for discharging uid under pressure into the cylinder in rear of the piston to move the latter and vterminal member into operative relation with the contact elements to close the circuit, means for simultaneously building up a pressure in advance of the piston operable to movethe latter and terminallmember to inoperative position irrespective of the uid pressure in rear of the piston, and means for regulating the time interval required to buildup sucient pressure in advance of the piston to move the latter to inoperative position.

6. A uid pressure operated switch comprising a pair of insulated contact elements connected to opposite sides of an electric circuit, a terminal bridge member adapted to establish an electrical connection between the contact elements 3to close the circuit,`a piston operatively connected to the terminal member,` a cylinder within which said piston is adapted to reciprocate, yieldable means normally urging said piston and terminal member to inoperative position,-

means for discharging fluid under pressure in rear vof 4the piston to` move the latter and terminal member vcarried thereby'in operative position with the contact 'elements to close the circuits, and means for building upa pressure in advance of the piston substantiallyA equal to the pressure discharged in rear of the piston permitting said yieldable means to return the piston normally urging said piston in one direction to holdsaid circuit closer out of engagement with said contacts, the fluid pressure from said source of fluid supply acting-to move said piston in the opposite direction, and a metering valve in said passage for regulating the flow of pressure fluid into said cylinder whereby the' time vinterval required'to operate said piston to close the circuit may be regulated.

` HENRY THOMAS PLATZ. 

